Recovery of oil from bituminous sands



Nov. 27, 1956 J. STEWART EFAL RECOVERY OF OIL FROM BITUMINOUS SANDS Filed July 1. 1955 in a mu F EQEEG est Q 1K 5 RN %-mx m3" 5v N: #255 mm M951 3 Iv mzotom A? mwmam 528m. Swag Q F N: 6 m E EBE G, K t 3 8 M23823 mmzqom 536 S B mQEZmQQmEI 5:20:35 A: 96+ a .& M931 mm I 98 v EMBB $28 Q23 6 Joseph Sfewan Stewari C Fulton United States Fatent Q 2,772,209 RECOVERY or on. FROM nrrmvnsous sis-Nos Application July 1, 1953, Serial No. 365,342 3 Claims. Cl. 196-14) The present invention relates to the recovary' of oil from bituminous sands. It relates more particular 7 improved system and process for the more efli'c nt recovery of optimum quantities of oil from oil-bearing minerals such as the so-called tar sands.

Bituminous sands or tar sands are well known in arious parts of the world. One of the mostimportant deposits is found in Alberta, Canada, along the Athabasca River and its tributaries. Layers of sand heavily impregnated or saturated with oil are found over a substantial area in this region. Other deposits which are less conspicuous or well known appear in numerous other places and doubtless rnany others are still to be discovered. These a; sands or bituminous sands are not to be confused oil shale which really contains no liquid oil as such but contains a solid organic material, kerogen, which can be cracked thermally to produce oil. By contrast, typical tar sands or bituminous sands contain 10 to' i672 by weight of a heavy viscous oil or bitumen as such. Ifl some areas, deposits containing as much as 100,000,000 barrels of such oil or bitumen persquare mile are known toeiiist. Notwithstanding" their abundance, to date no commercial- I feasible method for recovery has been developed.

In a copending application filed concurrently'he're'with by the present inventors,v Serial No. 305,343 a process and system are disclosed for extracting oilfrom shale by a thermal treatment in the presence of a hydrogen donordiluent material. The present application is 'sori'ilewhat similar but since oilshale and bituminous sands are c'juite different in their physical and chemical construction they must be processed differently and the present invention relates tothe bituminous sands.

In another copending. application filed concurrently herewith bJy'Langenone o'f the present inventorsna process is-diescribedwherein various heavy oils,v particularlypetfol'eum residual oils, may be upgraded by the'- wisest an inexpensive hydrogen donor and diluent-' material. Such process, described in detail and claimed in application Serial No. 365,335 is generally applicable to the present situation. However, bituminous sands present a particular' profile-m, since some 84' to; 90% or more" is-riiineral matter and the oils recovered therefrom are-not only of high viscosity but also contain high proportions of siilfur and other non-hydrocarbon materials which give rise to substantial problems in handling them.

It is therefore an object of the present invention to so treat the oil bearing sands as to recover optimum quantities of useful products from them at low cost. In part, this object is achieved by making use of an inexpensive hydrogen donor diluent, such as a partially hydrogenated thermal tar obtained from catalytic cracking operations on hydrocarbon fractions such as petroleum gas oils and the like. Preferably, the hydrogen donor diluents used for purposes of the present invention are of somewhat lower boiling range, in general, than those used in the copending applications mentioned above. In the present process it is preferred to use a donor-diluent "2,772,269 Patented Nov. 21, 1956 havinga boiling range within the limits" roughly of about 500 to 700 The lower boiling material makes it easier to strip the oil from the sand in later stages of the process. However, diluents boiling above 700 F. and new about 900 F. may be used in many cases without diiiiculiy; I

The diluent is preferably used in suflicient proportions to form a liquid. or pumpable slurr'y with the sand. For this pnr'ps e, with grade sands, the diluent should have a weight ratio of up to abouts to 1, based on the tar ohtenf of the sand. For sands of low bitumen or oil content,- even larger proportions may be needed, up to about 1 0 to l on the same basis. Using 5 to 10 parts of donor-diluent by" weight for each partof tar or bitumen,

to 600s c. f. of hydrogen per barrel of diluent is quite .dq i i It' islnot ays necessary to farm a pumpab e slurr of the sa 'id, though that is the method presently preferred. It issue possible to prepare a viscous paste by using, for example, about 1 part of diluent for each part of tar or bitumen. In this ease, the paste may be transferred by an extrlider type feeding device, as is known in the art. In case also, the hydrogen requirements, per of diluent, tend to be higher. Qvefall, diluent ratios may yary from afliout l to 1' to 10' to 1, compared with the bitumen content of the sand and the hydrogen added to thediluent may vary'froni as; little as abou t 501's asm u ch as 1000 s. C f. Or more per barrel of diluent: Q

In the preferred process, sand is broken and mixed rn1'n es'tb aseut 120 minutes; The process is preferably carried out under moderate pressure, e. g. up to p. s. ilgi, a pressure of about 200 p. s. il g'. being very satisfactory. However, the pres ure need be no greater than is nece ary' to prevent loss of volatile ingredients.

'I'he'sandsettles' gradually the bottom, as its oil content is earne and an phase forms at the top. The rate of sand settling [and the completeness of oil eitragcitioii varies'in pa'rtwith the viscosity of thelslurr y an in part with manage or agitationl T11; latter .shfoiild he so controlledas to obtain extraction of oil, consistentwi'th good through 'ut'. Ifithe avera'g'e residence time of the sand is within limits described above and the sand slurry isfree'fiowingektractionwill be'rea 'iiably'con'iplete. .With a residence time of 1 hour for'x'a'mple, anda ratio of diluent-tobitu meiiof 4:1, using a smperatiiiesf was; 7. E 'a dililiit; (if bblilifig fangeiabi5ut'500t6 700 F., armors of the bitumen may be extracted;

The extracted portion is then fractionated to obtain several cuts including one that is suitable for partial hydrogenation and recycling as a diluent. Bottoms may be partly or wholly recycled with the diluent, at least a small part preferably being discarded to prevent build-up of undesirable constituents.

The invention will be more fully understood by reference to the attached drawing where an embodiment is shown diagrammatically.

As shown in the drawing, oil sand is broken into small lumps or particles of a maximum size of 1 inch or less, preferably not over inch in average diameter. The subdivided bituminous sand is fed to a slurry tank 11 ,sand and to strip its. residual oil content.

through a line 13. There it is mixed by any conventional means, not shown, with a liquid donor-diluentfraction supplied through a line 15, to form a slurry, preferably a free flowing or pumpable slurry. I

The slurry leaves tank 11 through a line 17 and passes to a heating coil 19 and into a soaking and settling tank 21. Additional heat may be applied to or in tank 21 by conventional means if desired. In any case, the temperature of the slurry in the settler is brought up to at least 700 F. and not more than 1000 F., preferably between 750 and 900 F.

Agitation by a propeller or stirrer or, the equivalent is 'maintained in the tank21 so that the sand settles slowly 'to the bottom with a residence time between about and about 120 minutes, as previously described. Oil

moves to the top of the tank 21 and is drawn off through.

a line 23 to fractionator 25. The sand is taken out at the bottom through a line 27 to a receiver, shown as a 'fluid solids stripper vessel 29. Here a stripping fluid,

preferably steam, though an inert gas may be used, is introduced through one or more lines 31 to fiuidize the The spent sand may be withdrawn through a line 33, preferably to a heat exchanger to make use of its sensible heat. Thereafter it is discarded.

The oil is fractionated in fractionator 25 to obtain desired products such as gas through line 35, gasoline through line 37, light gas oil through line 39, a diluentdonor base material through line.41 (preferably boiling between $0001 550 and about 700 F.) and a heavy gas oil through line 43. Bottoms are withdrawn through a line'45, from which part may be purged through line 47. The remainder, or all if desired, may be recycled to the diluent line through line 49.

The stripped products from stripper vessel 29 go through line 51 to a condenser 53 where the steam is condensed and removed through a line 55. The oil products then go through line 57 to join the feed to the fractionator described above.

' In order to control the quality of the diluent, part of it may be purged from line 41 through line '59. The remainder is taken to a hydrogenator 61.' Here make-up thermal tar may be added, to keep the condensed ring aromatics content high, through a line 63. This ispreferably a tar from catalytic cracking of petroleum (gas oil), with the same general boiling range, i. e. above 500 F. and below 900 F. Gaseous hydrogen is added, from any suitable source such as a hydroformer, or the like, through line 65. 'As noted above, hydrogen requirements may vary between about 50 and 1000 s. c. f. per barrel of diluent, more or less, depending upon the ratio of 'dilu ent to bitumen, as wellas upon other factors such as pressure andtemperature in the soaker. Gas may be purged overhead through line 67, but preferably much or most of 'it is recycled through line 69. Hydrogenation is carried bituminous sands, the salient feature being particularly --the use of partially hydrogenated liquid donor-diluent of middle boiling range and at moderate temperatures. The use of thermal tar as'the diluent base is a particular feature. As suggested above a pasty mixture may be used instead of a liquid slurry in some cases and it is intended that the term slurry, when used in the claims Without further qualification shall cover both. The liquid slurry system and process is more flexible and is specifi- 10 .cally preferred.

What is claimed is: 7 1. The process of etficiently extracting oil frorn'bituminous sand which comprises breaking up said sand into small particles, forming a liquid slurry of said particles. 15 in a liquid hydrogenv donor-diluent of boiling range between about 500and about 700 F., feeding said slurry to a settling and soaking zone, heating said slurry noncatalytically and at a pressure sufiicient to prevent loss of volatile ingredients, a maximurn'of 500 p. s. i. g. to .a

temperature between about 750 and 900 F., allowing separating the residual oil so removed from said steam and passing said residual oil to a fractionation zone along with the oil separated from the sand in the settling and soaking zone, fractionating said oils to obtain gasoline, gas oil, a diluent base fraction, boiling between 500 and 30 700 F., and a bottoms fraction, bleeding off a portion of said diluent base fraction, adding a thermal tar of similar boiling point'from catalytic cracking of a petroleum fraction, partially hydrogenating said combined diluent base fraction and thenmal tar by adding 200 to 600 s. c. f. of

hydrogen gas thereto under hydrogenating conditions,

recycling the partially hydrogenated material to join said slurry, and adding said bottoms fraction thereto.

2. Process according to claim 1 wherein the ratio of donor diluent to bitumen in said sand is between 1 and 5/1.

40 3. Process according to claim 1 wherein a thin liquid pumpable slurry is formed.

References'Cited inthe file of this patent UNITED STATES PATENTS 1,327,572 Ryan Jan. 6, 1920 1,711,499. Hofsass May 7, 1929 1,778,515 Hampton Oct. 14, 1930 1,794,865 Pier et a1 Mar. 3, 1931 2,147,753 Pott et al.. Feb. 21, 1939 2,426,929., Greensfelder Sept. 2, 1947 2,436,938 Scharmann et a1 Mar. 2, 19 48 7 2,502,598 Johnson- Apr. 4, 1950 2,587,729 Huif Mar. 4, 1952 2,601,257v Buchan June 24, 1952 2,614,067 Reed et a1 Oct. 14, 1952 OTHER REFERENCES Hodgman et al.: Handbook of Chemistry and Physics,

35th ed., pages 732 and 733, published by Chemical Rubber Publishing Co., Cleveland, Ohio (1953), 

1. THE PROCESS OF EFFICIENTLY EXTRACTING OIL FROM BITUMINOUS SAND WHICH COMPRISES BREAKING UP SAID SAND INTO SMALL PARTICLES, FORMING A LIQUID SLURRY OF SAID PARTICLES IN A LIQUID HYDROGEN DONOR-DILUENT OF BOILING RANGE BETWEEN ABOUT 500* AND ABOUT 700* F., FEEDING SAID SLURRY TO A SETTLING AND SOAKING ZONE, HEATING SAID SLURRY NONCATALYTICALLY AND AT A PRESSURE SUFFICIENT TO PREVENT LOSS OF VOLATILE INGREDIENTS, A MAXIMUM OF 500 P.S.I.G. TO A TEMPERATURE BETWEEN ABOUT 750* AND 900* F., ALLOWING A PERIOD OF ABOUT 10 TO 120 MINUTES FOR SAID SAND TO SEPARATE FROM SAID OIL BY PHASE FORMATION, PASSING THE SAND TO A STRIPPING ZONE, FLUIDIZING SAND IN SAID STRIPPING ZONE WITH STEAM TO REMOVE RESIDUAL OIL THEREFROM, SEPARATING THE RESIDUAL OIL SO REMOVED FROM SAID STEAM AND PASSING SAID RESIDUAL OIL TO A FRACTIONATION ZONE ALONG WITH THE OIL SEPARATED FROM THE SAND IN THE SETTLING AND SOAKING ZONE, FRACTIONATING SAID OILS TO OBTAIN GASOLINE, GAS OIL, A DILUENT BASE FRACTION, BOILING BETWEEN 500* AND 700* F., AND A BOTTOMS FRACTION, BLEEDING OFF A PORTION OF SAID DILUENT BASE FRACTION, ADDING A THERMAL TAR OF SIMILAR BOILING POINT FROM CATALYTIC CRACKING OF A PETROLEUM FRACTION, PARTIALLY HYDROGENATING SAID COMBINED DILUENT BASE FRACTION AND THERMAL TAR BY ADDING 200 TO 600 S.C.F. OF HYDROGEN GAS THERETO UNDER HYDROGENATING CONDITIONS, RECYCLING THE PARTIALLY HYDROGENATED MATERIAL TO JOIN SAID SLURRY, AND ADDING SAID BOTTOMS FRACTION THERETO. 